int fscrypt_get_crypt_info(struct inode *inode) { struct fscrypt_info *crypt_info; struct fscrypt_context ctx; struct crypto_skcipher *ctfm; const char *cipher_str; int keysize; u8 *raw_key = NULL; int res; res = fscrypt_initialize(inode->i_sb->s_cop->flags); if (res) return res; if (!inode->i_sb->s_cop->get_context) return -EOPNOTSUPP; retry: crypt_info = ACCESS_ONCE(inode->i_crypt_info); if (crypt_info) { if (!crypt_info->ci_keyring_key || key_validate(crypt_info->ci_keyring_key) == 0) return 0; fscrypt_put_encryption_info(inode, crypt_info); goto retry; } res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx)); if (res < 0) { if (!fscrypt_dummy_context_enabled(inode)) return res; ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1; ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS; ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS; ctx.flags = 0; } else if (res != sizeof(ctx)) { return -EINVAL; } if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1) return -EINVAL; if (ctx.flags & ~FS_POLICY_FLAGS_VALID) return -EINVAL; crypt_info = kmem_cache_alloc(fscrypt_info_cachep, GFP_NOFS); if (!crypt_info) return -ENOMEM; crypt_info->ci_flags = ctx.flags; crypt_info->ci_data_mode = ctx.contents_encryption_mode; crypt_info->ci_filename_mode = ctx.filenames_encryption_mode; crypt_info->ci_ctfm = NULL; crypt_info->ci_keyring_key = NULL; memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor, sizeof(crypt_info->ci_master_key)); res = determine_cipher_type(crypt_info, inode, &cipher_str, &keysize); if (res) goto out; /* * This cannot be a stack buffer because it is passed to the scatterlist * crypto API as part of key derivation. */ res = -ENOMEM; raw_key = kmalloc(FS_MAX_KEY_SIZE, GFP_NOFS); if (!raw_key) goto out; if (fscrypt_dummy_context_enabled(inode)) { memset(raw_key, 0x42, FS_AES_256_XTS_KEY_SIZE); goto got_key; } res = validate_user_key(crypt_info, &ctx, raw_key, FS_KEY_DESC_PREFIX, FS_KEY_DESC_PREFIX_SIZE); if (res && inode->i_sb->s_cop->key_prefix) { u8 *prefix = NULL; int prefix_size, res2; prefix_size = inode->i_sb->s_cop->key_prefix(inode, &prefix); res2 = validate_user_key(crypt_info, &ctx, raw_key, prefix, prefix_size); if (res2) { if (res2 == -ENOKEY) res = -ENOKEY; goto out; } } else if (res) { goto out; } got_key: ctfm = crypto_alloc_skcipher(cipher_str, 0, 0); if (!ctfm || IS_ERR(ctfm)) { res = ctfm ? PTR_ERR(ctfm) : -ENOMEM; printk(KERN_DEBUG "%s: error %d (inode %u) allocating crypto tfm\n", __func__, res, (unsigned) inode->i_ino); goto out; } crypt_info->ci_ctfm = ctfm; crypto_skcipher_clear_flags(ctfm, ~0); crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_REQ_WEAK_KEY); res = crypto_skcipher_setkey(ctfm, raw_key, keysize); if (res) goto out; kzfree(raw_key); raw_key = NULL; if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) != NULL) { put_crypt_info(crypt_info); goto retry; } return 0; out: if (res == -ENOKEY) res = 0; put_crypt_info(crypt_info); kzfree(raw_key); return res; }
int fscrypt_get_encryption_info(struct inode *inode) { struct fscrypt_info *crypt_info; struct fscrypt_context ctx; struct crypto_skcipher *ctfm; const char *cipher_str; int keysize; u8 *raw_key = NULL; int res; if (inode->i_crypt_info) return 0; res = fscrypt_initialize(inode->i_sb->s_cop->flags); if (res) return res; res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx)); if (res < 0) { if (!fscrypt_dummy_context_enabled(inode) || inode->i_sb->s_cop->is_encrypted(inode)) return res; /* Fake up a context for an unencrypted directory */ memset(&ctx, 0, sizeof(ctx)); ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1; ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS; ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS; memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE); } else if (res != sizeof(ctx)) { return -EINVAL; } if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1) return -EINVAL; if (ctx.flags & ~FS_POLICY_FLAGS_VALID) return -EINVAL; crypt_info = kmem_cache_alloc(fscrypt_info_cachep, GFP_NOFS); if (!crypt_info) return -ENOMEM; crypt_info->ci_flags = ctx.flags; crypt_info->ci_data_mode = ctx.contents_encryption_mode; crypt_info->ci_filename_mode = ctx.filenames_encryption_mode; crypt_info->ci_ctfm = NULL; crypt_info->ci_essiv_tfm = NULL; memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor, sizeof(crypt_info->ci_master_key)); res = determine_cipher_type(crypt_info, inode, &cipher_str, &keysize); if (res) goto out; /* * This cannot be a stack buffer because it is passed to the scatterlist * crypto API as part of key derivation. */ res = -ENOMEM; raw_key = kmalloc(FS_MAX_KEY_SIZE, GFP_NOFS); if (!raw_key) goto out; res = validate_user_key(crypt_info, &ctx, raw_key, FS_KEY_DESC_PREFIX, keysize); if (res && inode->i_sb->s_cop->key_prefix) { int res2 = validate_user_key(crypt_info, &ctx, raw_key, inode->i_sb->s_cop->key_prefix, keysize); if (res2) { if (res2 == -ENOKEY) res = -ENOKEY; goto out; } } else if (res) { goto out; } ctfm = crypto_alloc_skcipher(cipher_str, 0, 0); if (!ctfm || IS_ERR(ctfm)) { res = ctfm ? PTR_ERR(ctfm) : -ENOMEM; pr_debug("%s: error %d (inode %lu) allocating crypto tfm\n", __func__, res, inode->i_ino); goto out; } crypt_info->ci_ctfm = ctfm; crypto_skcipher_clear_flags(ctfm, ~0); crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_REQ_WEAK_KEY); /* * if the provided key is longer than keysize, we use the first * keysize bytes of the derived key only */ res = crypto_skcipher_setkey(ctfm, raw_key, keysize); if (res) goto out; if (S_ISREG(inode->i_mode) && crypt_info->ci_data_mode == FS_ENCRYPTION_MODE_AES_128_CBC) { res = init_essiv_generator(crypt_info, raw_key, keysize); if (res) { pr_debug("%s: error %d (inode %lu) allocating essiv tfm\n", __func__, res, inode->i_ino); goto out; } } if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) == NULL) crypt_info = NULL; out: if (res == -ENOKEY) res = 0; put_crypt_info(crypt_info); kzfree(raw_key); return res; }